Piezometric biosensors for anti-apoptotic protein survivin based on buried positive-potential barrier and immobilized monoclonal antibodies

Parallel SPR and QCM-D Quantitative Analysis of CD9, CD63, and CD81 Tetraspanins: A Simple and Sensitive Way to Determine the Concentration of Extracellular Vesicles Isolated from Human Lung Cancer Cells

Tetraspanins, including CD9, CD63, and CD81, are transmembrane biomarkers that play a crucial role in regulating cancer cell proliferation, invasion, and metastasis, as well as plasma membrane dynamics and protein trafficking. In this study, we developed simple, fast, and sensitive immunosensors to determine the concentration of extracellular vesicles (EVs) isolated from human lung cancer cells using tetraspanins as biomarkers. We employed surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation (QCM-D) as detectors. The monoclonal antibodies targeting CD9, CD63, and CD81 were oriented vertically in the receptor layer using either a protein A sensor chip (SPR) or a cysteamine layer that modified the gold crystal (QCM-D) without the use of amplifiers. The SPR studies demonstrated that the interaction of EVs with antibodies could be described by the two-state reaction model. Furthermore, the EVs' affinity to monoclonal antibodies against tetraspanins decreased in the following order: CD9, CD63, and CD81, as confirmed by the QCM-D studies. The results indicated that the developed immunosensors were characterized by high stability, a wide analytical range from 6.1 × 10⁴ particles·mL^-1 to 6.1 × 10⁷ particles·mL^-1, and a low detection limit (0.6-1.8) × 10⁴ particles·mL^-1. A very good agreement between the results obtained using the SPR and QCM-D detectors and nanoparticle tracking analysis demonstrated that the developed immunosensors could be successfully applied to clinical samples.

DNA Aptamer Beacon Probe (ABP) for Monitoring of Adenosine Triphosphate Level in SW480 Cancer Cells Treated with Glycolysis Inhibitor 2-Deoxyglucose

Early cancer screening enables timely detection of carcinogenesis, and aids in prompt clinical intervention. Herein, we report on the development of a simple, sensitive, and rapid fluorometric assay based on the aptamer probe (aptamer beacon probe, ABP) for monitoring the energy-demand biomarker adenosine triphosphate (ATP), an essential energy source that is released into the tumor microenvironment. Its level plays a significant role in risk assessment of malignancies. The operation of the ABP for ATP was examined using solutions of ATP and other nucleotides (UTP, GTP, CTP), followed by monitoring of ATP production in SW480 cancer cells. Then, the effect of a glycolysis inhibitor, 2-deoxyglucose (2-DG), on SW480 cells was investigated. The stability of predominant ABP conformations in the temperature range of 23-91 °C and the effects of temperature on ABP interactions with ATP, UTP, GTP, and CTP were evaluated based on quenching efficiencies (QE) and Stern-Volmer constants (K_SV). The optimized temperature for best selectivity of ABP toward ATP was 40 °C (K_SV = 1093 M^-1, QE = 42%). We have found that the inhibition of glycolysis in SW480 cancer cells by 2-deoxyglucose resulted in lowering of ATP production by 31.7%. Therefore, monitoring and modulation of ATP concentration may aid in future cancer treatment.

Facile Label-Free Electrochemical DNA Biosensor for Detection of Osteosarcoma-Related Survivin Gene

A sensitive and selective electrochemical deoxyribonucleic acid (DNA) biosensor was developed for the determination of a osteosarcoma-related survivin gene by using celestine blue (CB) as a label-free hybridization indicator. The proposed strategy adopted a facile and low-cost working electrode with no need for other substances for electrode or DNA functionalization. The interaction mode between CB and DNA was studied by electrochemical and spectroscopic approaches, illustrating that the possible mode was intercalation with a binding number of 2 and a binding constant β of 10^12.87. Moreover, the label-free electrochemical DNA biosensor exhibited a good linear relationship toward the target gene in a range from 1.00 nM to 50.00 nM with a detection limit as low as 0.046 nM using 3σ estimating system. This facile and low-cost electrochemical method realized the rapid detection and accurate quantification of the target sequence in complicated serum samples, endowing its promising potential in the diagnosis and monitoring of genetic diseases.

Poly(amidoamine) dendrimer immunosensor for ultrasensitive gravimetric and electrochemical detection of matrix metalloproteinase-9

Monitoring the level of matrix metalloproteinase-9 (MMP-9) and inhibiting its expression is important for the diagnosis and treatment of various diseases. However, the analysis of MMP-9 is challenging owing to its very low content in the blood, especially at the early stages of diseases. Therefore, we developed an ultrasensitive and easy-to-use immunosensor based on a three-dimensional (3D) bioplatform for the determination of the total MMP-9 concentration in plasma. The used 3D bioplatform (G2 poly(amidoamine) dendrimer; PAMAM) improved the sensitivity of the determination by significantly expanding the surface area of the receptor layer. The antigen-antibody recognition process was controlled by quartz crystal microbalance with dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS). The effect of the orientation of antibody molecules in the sensing layer on the work parameters of the immunosensor was analyzed using unmodified PAMAM (PAMAM-NH₂) and PAMAM functionalized with -COOH groups (PAMAM-COOH). The developed immunosensor based on PAMAM-NH₂ was characterized by a lower detection limit (LOD = 2.0 pg⋅mL^-1) and wider analytical range (1·10^-4 - 5 μg⋅mL^-1 for EIS and QCM-D) compared to PAMAM-COOH immunosensor (EIS: 1·10^-4 - 0.5 μg⋅mL^-1; QCM-D: 5·10^-4 - 0.5 μg⋅mL^-1). The functionality of the proposed device was verified in spiked plasma. The recoveries determined in commercial human and rat plasma and noncommercial rat plasma were very close to the value of 100% and in the range of 96-120% for Au/PAMAM-NH₂/Ab and Au/PAMAM-COOH/Ab immunosensors, respectively. The designed analytical devices showed high selectivity and sensitivity without the use of any amplifiers such as metal nanoparticles or enzymes.

Recent progress in the early detection of cancer based on CD44 biomarker; nano-biosensing approaches

CD44 is a cell matrix adhesion molecule overexpressed on the cell surfaces of the major cancers. CD44 as a cancer-related biomarker has an essential role in the invasion and metastasis of cancer. The detection and quantification of CD44 can provide essential information useful for clinical cancer diagnosis. In this regard, biosensors with sensitive and specific properties, give prominence to the development of CD44 detection platforms. To date, various aptamer-based sensitive-enhancers together with nanoparticles (NPs) have been combined into the biosensors systems to provide an innovative biosensing method (aptasensors/nano-aptasensors) with substantially improved detection limit. This review article discusses the recent advances in the field of biosensors, nanobiosensors, and aptasensors for the quantitative determination of CD44 and the detection of CD44-expressing cancer cells.

Detection of Low Density Lipoprotein-Comparison of Electrochemical Immuno- and Aptasensor

An elevated level of low density lipoprotein (LDL) can lead to the cardiovascular system-related diseases, such as atherosclerosis and others. Therefore, fast, simple, and accurate methods for LDL detection are very desirable. In this work, the parameters characterizing the electrochemical immuno-and aptasensor for detection of LDL have been compared for the first time. An immunosensor has been designed, for which the anti-apolipoprotein B-100 antibody was covalently attached to 4-aminothiophenol (4-ATP) on the surface of the gold electrode. In the case of an aptasensor, the gold electrode was modified in a mixture of ssDNA aptamer specific for LDL modified with –SH group and 6-mercaptohexanol. Square-wave voltammetry has been used for detection of LDL in PBS containing redox active marker, [Fe(CN)₆]^3−/4−. Our results show the linear dependence of [Fe(CN)₆]^3−/4− redox signal changes on LDL concentration for both biosensors, in the range from 0.01 ng/mL to 1.0 ng/mL. The limit of detection was 0.31 and 0.25 ng/mL, for immuno- and aptasensor, respectively. Whereas slightly better selectivity toward human serum albumin (HSA), high density lipoprotein (HDL), and malondialdehyde modified low density lipoprotein (MDA-LDL) has been observed for aptasensor. Moreover, the other components of human blood serum samples did not influence aptasensor sensitivity.

Combination of ultrathin micro-patterned MXene and PEDOT: Poly(styrenesulfonate) enables organic electrochemical transistor for amperometric determination of survivin protein in children osteosarcoma

An ultrathin micro-patterned MXene/PEDOT:PSS-based organic electrochemical transistor biosensor was constructed, which can significantly amplify the amperometric signal and transistor's performance. A novel interdigitated OECTs biosensor has been developed for reliable determination of survivin for the following considerations: (1) The synergistic effect of intercalated MXene and ionic PEDOT:PSS enhanced the mobility and volumetric capacitance of OECTs biosensor. (2) Compared with the best previous literatures, our assay demonstrated enhanced detection limit of survivin down to 10 pg mL^-1, as well as satisfactory selectivity, reproducibility, and reliability. (3) Comparison of OECTs against commercial ELISA kit yielded favorable linearity (Y = 1.0015*X + 0.0039) and correlation coefficient (R² = 0.9717). Those advantages are expected to pave the way to design of an OECTs biosensor with robustness, non-invasiveness, and miniaturization for the point-of-care applications.

Therapeutic Attributes of Endocannabinoid System against Neuro-Inflammatory Autoimmune Disorders

In humans, various sites like cannabinoid receptors (CBR) having a binding affinity with cannabinoids are distributed on the surface of different cell types, where endocannabinoids (ECs) and derivatives of fatty acid can bind. The binding of these substance(s) triggers the activation of specific receptors required for various physiological functions, including pain sensation, memory, and appetite. The ECs and CBR perform multiple functions via the cannabinoid receptor 1 (CB1); cannabinoid receptor 2 (CB2), having a key effect in restraining neurotransmitters and the arrangement of cytokines. The role of cannabinoids in the immune system is illustrated because of their immunosuppressive characteristics. These characteristics include inhibition of leucocyte proliferation, T cells apoptosis, and induction of macrophages along with reduced pro-inflammatory cytokines secretion. The review seeks to discuss the functional relationship between the endocannabinoid system (ECS) and anti-tumor characteristics of cannabinoids in various cancers. The therapeutic potential of cannabinoids for cancer-both in vivo and in vitro clinical trials-has also been highlighted and reported to be effective in mice models in arthritis for the inflammation reduction, neuropathic pain, positive effect in multiple sclerosis and type-1 diabetes mellitus, and found beneficial for treating in various cancers. In human models, such studies are limited; thereby, further research is indispensable in this field to get a conclusive outcome. Therefore, in autoimmune disorders, therapeutic cannabinoids can serve as promising immunosuppressive and anti-fibrotic agents.

Differential colorimetric nanobiosensor array as bioelectronic tongue for discrimination and quantitation of multiple foodborne carcinogens

Foodborne amides, specifically acrylamide, are vitally important for food safety and security, as they are the most common food toxicants and suspected human carcinogens. A facile and novel differential-based colorimetric nanobiosensor array composed of three surface-bioengineered gold nanoparticles (AuNPs) was developed for the rapid detection, differentiation, and quantification of acrylamide and six analogues. Diverse cross-reactive receptors demonstrated differential binding affinities toward target analytes, resulting in distinctive AuNP aggregation behaviors and distinguishable response patterns. The sensor array, integrated with principal component analysis and hierarchical cluster analysis, accurately discriminated foodborne amides based on their amine subgroups, International Agency for Research on Cancer (IARC) carcinogen classifications, and food additive types, even at ultra-low concentrations (500 pM). Additionally, the sensor array successfully differentiated non-targeted analytes by sweetener and food ingredients types with 100% correct classification. Partial least squares regression outcomes exhibited high correlation coefficients (R2 > 0.95). Thus, the sensor array has practical potential for food safety monitoring in the food and beverage industries.

Diagnosis of COVID-19 for controlling the pandemic: A review of the state-of-the-art

To date, health organizations and countries around the world are struggling to completely control the spread of the coronavirus disease 2019 (COVID-19). Scientists and researchers are developing tests for the rapid detection of individuals who may carry the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while striving to find a suitable vaccine to immunize healthy individuals. As there are clinically reported cases of asymptomatic carriers of SARS-CoV-2, fast and accurate diagnosis plays an important role in the control and further prevention of this disease. Herein, we present recent technologies and techniques that have been implemented for the diagnosis of COVID-19. We summarize the methods created by different research institutes as well as the commercial devices and kits developed by companies for the detection of SARS-CoV-2. The description of the existing methods is followed by highlighting their advantages and challenges. Finally, we propose some promising techniques that could potentially be applied to the detection of SARS-CoV-2, and tracing the asymptomatic carriers of COVID-19 rapidly and accurately in the early stages of infection, based on reviewing the research studies on the detection of similar infectious viruses, especially severe acute respiratory syndrome (SARS) coronavirus, and Middle East respiratory syndrome (MERS) coronavirus.

Recognition of M2 type tumor-associated macrophages with ultrasensitive and biocompatible photoelectrochemical cytosensor based on Ce doped SnO2/SnS2 nano heterostructure

Tumor-associated macrophages (TAMs) play central roles in the regulation of tumor growth. TAMs can be differentiated into M1 and M2 types, which are responsible for the inhibition and growth of tumor tissues, respectively. Recognition of M2-TAMs is significant for the diagnosis and therapy of cancer, which is however severely limited due to the deficiency of selective and sensitive photoelectrochemical sensors. In this work, using Ce doped SnO₂/SnS₂ nano heterostructure as the highly sensitive platform, a photoelectrochemical sensor enabling the recognition of M2-TAMs was fabricated for the first time. By the decoration of CD163 antibody on the platform, the ultrasensitive photoelectrochemical sensor can selectively detect the CD163 protein on the surface of M2-TAMs. To our best knowledge, this is the first demonstration for recognition of M2-TAMs using photoelectrochemical method. The fabricated cytosensor has ultra-sensitive photocurrent response, applicable biological compatibility, high selectivity and relatively wide linear sensing range (5 × 10¹ to 1 × 10⁵ cells/ml) with a low detection limit (50 cells/ml) for the detection of M2-TAMS. This kind of PEC cytosensor would provide a novel analysis and detection strategy for M2-TAMs.

A novel sandwich-type SERS immunosensor for selective and sensitive carcinoembryonic antigen (CEA) detection

Monitoring the malignant tumors via cancer biomarkers is very significant process. Nonetheless, the practical clinical applications need selective and sensitive analytical methods/techniques. In this study, a novel sandwich type immunosensor based on surface-enhanced raman scattering (SERS) was presented including 4-mercaptobenzoic acid labeled MoS₂ nanoflowers@Au nanoparticles (MoS₂ NFs@Au NPs/ MBA) as CEASERS tag and Fe₃O₄@Au nanoparticles functionalized delaminated Ti₃C₂T_x MXene (Fe₃O₄ NPs@Au NPs/d-Ti₃C₂T_X MXene) as SERS magnetic supporting substrate for carcinoembryonic antigen (CEA) detection. Especially, the determination of single molecule by using SERS method enables early diagnosis of major diseases. In addition, this technique can be utilized for multiplex analyzes owing to narrow well-resolved peaks. The prepared CEASERS tag and SERS magnetic supporting substrate were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR). A linearity of 0.0001-100.0 ng mL^-1 was observed with high sensitivity. Finally, sandwich type immunosensor demonstrated good selectivity and stability for target CEA recognition in plasma sample.

Aqueous two-phase system antibody confinement enables cost-effective analysis of protein analytes by sandwich enzyme-linked immunosorbent assay with minimal optical crosstalk

An aqueous two-phase system formed from polyethylene glycol and dextran was used to uniformly coat the bottom surfaces of the wells of standard 96-well assay plates with capture and detection antibodies to improve the performance and cost-effectiveness of sandwich enzyme-linked immunosorbent assay (ELISA). Using this approach, limits of detection and linear dynamic range values comparable to those obtained for conventional sandwich ELISA were obtained using considerably lower antibody quantities due to the much lower reagent volumes required when antibodies are applied in a dextran solution beneath a polyethylene glycol overlay. Confinement of the antibody reagents to the bottom surfaces of the wells within the dextran phase also dramatically decreased the optical crosstalk present between neighboring wells when using transparent microplates. Adaptation of the conventional single sandwich ELISA for aqueous two-phase system antibody confinement was demonstrated by analysis of standard curves for C-reactive protein, transforming growth factor beta 1, and the chemokine CXCL10.

Differential-based biosensor array for fluorescence-chemometric discrimination and the quantification of subtle chloropropanols by cross-reactive serum albumin scaffolding

Food contamination is a serious concern because of a high level of chemicals in food causes severe health issues. Safeguarding the public from the risk of adulterated foods has become a challenging mission. Chloropropanols are of importance to food safety and food security because they are common chemical food contaminants and believed to be carcinogenic to humans. In chemical sensing, chloropropanols are challenging analytes owing to the lacking diversity of functional groups and difficulty in targeting the hydroxyl group in aqueous environments. Moreover, because of their small molecular size, the compositions of chloropropanols remain challenging for achieving chromatographic determination. Herein, to simulate human smell and taste sensations, serum albumins, which are protein-based receptors, were introduced as low-selective receptors for differential sensing. Utilizing serum albumins, a fluorophore (PRODAN), and an additive (ascorbic acid), a differential-based optical biosensor array was developed to detect and differentiate chloropropanols. By integrating the sensor array with linear discriminant analysis (LDA), four chloropropanols were effectively differentiated based on their isomerism properties and the number of the hydroxyl groups, even at ultra-low concentration (5 nM). This concentration is far below the maximum tolerable level of 0.18 μM for chloropropanols. The sensing array was then employed for chloropropanols differentiation and quantification in the complex mixtures (e.g., synthetic soy and dark soy sauces). Leave-one-out cross-validation (LOOCV) analysis demonstrated 100% accurate classification for all tests. These results signify our differential sensing array as a practical and powerful tool to speedily identify, differentiate, and even quantify chloropropanols in food matrices.

A Mechanism of Gold Nanoparticle Aggregation by Immunoglobulin G Preparation

Conjugates of gold nanoparticles (GNPs) and antibodies are widely used in various fields of biochemistry and microbiology. However, the procedure for obtaining such conjugates remains precarious, and the properties of conjugates differ significantly for different antibody clones. One of the most common problems is the aggregation of GNPs in the course of their conjugation with antibodies. This article considers an example of the conjugation of monoclonal antibodies with non-stable aggregating product. The composition of the antibody preparation was studied using electrophoresis, asymmetrical flow field-flow fractionation, and ultracentrifugation. It was shown that the component that causes the aggregation of the GNPs is the light chains of immunoglobulins that appear due to the spontaneous decay of the antibodies. After separation of the fraction with a molecular weight of less than 30 kDa, stable conjugates of antibodies with GNPs were obtained. The high functional activity of the obtained conjugates was confirmed by immunochromatography.

Ethanol vs. water: influence of the terminal functional group of the alkyl chain and environment of the self-assembly process on electron transport through the thiol layer

Self-assembly of alkanethiol chains on metallic surfaces is a spontaneous process which leads to the formation of highly ordered layers. However, the organization of the thiol chains on the surface strongly depends on the intermolecular interactions between the terminal groups in the chain. The solution environment also plays an important role. In this paper we present the effect of solution solvent (water and ethanol) and the presence of various hydrophilic terminal groups (–OH, –NH₂ and –COOH) on the quality and electrochemical properties of the formed alkanethiol layers. In the studies we applied voltammetry, atomic force microscopy and quartz crystal microbalance to characterize the morphology, packing density and ability to electron exchange through the thiol layer. The blocking properties of the formed SAMs expressed as the electron-transfer rate constant as well as their organization have been examined using a model electrochemical probe, Fe(CN)₆³⁻. With the increase in the polarity of the terminal functional group the regularity of the thiol layer decreased.

The organization of the thiol chains on the surface strongly depends on the intermolecular interactions between the terminal groups in the chain and the solution environment.

A magnetic SERS immunosensor for highly sensitive and selective detection of human carboxylesterase 1 in human serum samples

Hepatocellular carcinoma (HCC) is a common and lethal cancer. New serum markers for detecting HCC are urgently needed. Human carboxylesterase 1 (hCE1) is an important member of the serine hydrolase superfamily and is closely related to the occurrence of HCC. It can be used as a good serum marker for early diagnosis of HCC. Here, we developed a surface enhanced Raman scattering (SERS)- based magnetic immunosensor that specifically recognizes and detects trace amounts of hCE1 in human serum via a sandwich structure consisting of a SERS tags, magnetic supporting substrates, and target antigen (hCE1). The SERS tags are 4-mercaptobenzoic acid (4-MBA)-labeled AgNPs, and the SERS supporting substrates are composed of a raspberry-like morphology of Fe₃O₄@SiO₂@AgNPs magnetic nanocomposites surface-functionalized with a hCE1 antibody. The prepared SERS magnetic immunosensor exhibits excellent selectivity and extremely high sensitivity for hCE1 detection. The SERS signal and logarithm of hCE1 concentration presented a wide linear response range of 0.1 ng mL^-1 to 1.0 mg mL^-1, and the detection limit of hCE1 was 0.1 ng mL^-1. The results indicate that the immunosensor can be used for the rapid determination of hCE1 in human serum without a complicated sample pre-treatment. Furthermore, the immunosensor has good reproducibility and stability, and has a promising prospect for the quantitative detection of other tumor markers in early clinical diagnosis.

Toward early cancer detection: Focus on biosensing systems and biosensors for an anti-apoptotic protein survivin and survivin mRNA

The development of biosensors for cancer biomarkers has recently been expanding rapidly, offering promising biomedical applications of these sensors as highly sensitive, selective, and inexpensive bioanalytical tools that can provide alternative methodology to that afforded by the advanced hyphenated-instrumental techniques. In this review, we focus particularly on the detection of a member of the inhibitor of apoptosis proteins (IAP) family, protein survivin (Sur), a ubiquitous re-organizer of the cell life cycle with the ability to inhibit the apoptosis and induce an enhanced proliferation leading to the unimpeded cancer growth and metastasis. Herein, we critically evaluate the progress in the development of novel biosensing systems and biosensors for the detection of two survivin (Sur) biomarkers: the Sur protein and its messenger RNA (Sur mRNA), including immunosensors, electrochemical piezo- and impedance-sensors, electrochemi-luminescence biosensors, genosensors based on oligonucleotide molecular beacons (MBs) with fluorescent or electrochemical transduction, as well as the microfluidic and related analytical platforms based on solution chemistry. The in-situ applications of survivin biomarkers' detection technologies to equip nanocarriers of the controlled drug delivery systems with MB-based fluorescence imaging capability, apoptosis control, and mitigation of the acquired drug resistance are also presented and critically evaluated. Finally, we turn the attention to the application of biosensors for the analysis of Sur biomarkers in exosomes and circulating tumor cells for a non-invasive liquid biopsy. The prospect of a widespread screening for early cancers, based on inexpensive point-of-care testing using biosensors and multiplex biosensor arrays, as a means of reducing the high cancer fatality rate, is discussed.

Regulation of Survivin Isoform Expression by GLI Proteins in Ovarian Cancer

Ovarian cancer (OC) is the most lethal female gynecological malignancy, mostly due to diagnosis in late stages when treatment options are limited. Hedgehog-GLI (HH-GLI) signaling is a major developmental pathway involved in organogenesis and stem cell maintenance, and is activated in OC. One of its targets is survivin (BIRC5), an inhibitor of apoptosis protein (IAP) that plays a role in multiple processes, including proliferation and cell survival. We wanted to investigate the role of different GLI proteins in the regulation of survivin isoform expression (WT, 2α, 2B, 3B, and Δex3) in the SKOV-3 OC cell line. We demonstrated that survivin isoforms are downregulated in GLI1 and GLI2 knock-out cell lines, but not in the GLI3 knock-out. Treatment of GLI1 knock-out cells with GANT-61 shows an additional inhibitory effect on several isoforms. Additionally, we examined the expression of survivin isoforms in OC samples and the potential role of BIRC5 polymorphisms in isoform expression. Clinical samples showed the same pattern of survivin isoform expression as in the cell line, and several BIRC5 polymorphisms showed the correlation with isoform expression. Our results showed that survivin isoforms are regulated both by different GLI proteins and BIRC5 polymorphisms in OC.

Hairpin-Hairpin Molecular Beacon Interactions for Detection of Survivin mRNA in Malignant SW480 Cells

Cancer biomarkers offer unique prospects for the development of cancer diagnostics and therapy. One of such biomarkers, protein survivin (Sur), exhibits strong antiapoptotic and proliferation-enhancing properties and is heavily expressed in multiple cancers. Thus, it can be utilized to provide new modalities for modulating the cell-growth rate, essential for effective cancer treatment. Herein, we have focused on the development of a new survivin-based cancer detection platform for colorectal cancer cells SW480 using a turn-on fluorescence oligonucleotide molecular beacon (MB) probe, encoded to recognize Sur messenger RNA (mRNA). Contrary to the expectations, we have found that both the complementary target oligonucleotide strands as well as the single- and double-mismatch targets, instead of exhibiting the anticipated simple random conformations, preferentially formed secondary structure motifs by folding into small-loop hairpin structures. Such a conformation may interfere with, or even undermine, the biorecognition process. To gain better understanding of the interactions involved, we have replaced the classical Tyagi-Kramer model of interactions between a straight target oligonucleotide strand and a hairpin MB with a new model to account for the hairpin-hairpin interactions as the biorecognition principle. A detailed mechanism of these interactions has been proposed. Furthermore, in experimental work, we have demonstrated an efficient transfection of malignant SW480 cells with SurMB probes containing a fluorophore Joe (SurMB-Joe) using liposomal nanocarriers. The green emission from SurMB-Joe in transfected cancer cells, due to the hybridization of the SurMB-Joe loop with Sur mRNA hairpin target, corroborates Sur overexpression. On the other hand, healthy human-colon epithelial cells CCD 841 CoN show only negligible expression of survivin mRNA. These experiments provide the proof-of-concept for distinguishing between the cancer and normal cells by the proposed hairpin-hairpin interaction method. The single nucleotide polymorphism sensitivity and a low detection limit of 26 nM (S/N = 3σ) for complementary targets have been achieved.

Fabrication of an immunosensor for early and ultrasensitive determination of human tissue plasminogen activator (tPA) in myocardial infraction and breast cancer patients

Sensitive detection of biomarkers will mean accurate and early diagnosis of diseases. A tissue plasminogen activator (tPA) has a crucial role in many cardiovascular diseases and it is related to many processes such as angiogenesis in cancer cells. Therefore, sensitive determination of tPA is important in diagnosis and clinical research. tPA monoclonal antibody was covalently attached onto single-wall carbon nanotubes (SWCNTs) using diimide-activated imidation coupling. Functionalized SWCNTs were immobilized onto a glassy carbon electrode and the modification process was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), SEM, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Cyclic voltammograms (CVs) in a scan rate of 100 mVs^-1 was studied and comparisons were made between the modified glassy carbon electrodes (immobilized with antibodies) as a working electrode before and after the formation of tPA-antibody complex. Results of the SDS-PAGE demonstrated that the antibody was covalently and site directly attached to the SWCNTs. The fabricated biosensor provided a good linear response range from 0.1 to 1.0 ng mL^-1 with a low detection limit of 0.026 ng mL^-1. The immunosensor showed selectivity, reproducibility, good sensitivity, and acceptable stability. Satisfactory results were observed for early and sensitive determination of tPA in human serum samples. For the first time, such specific biosensor is currently being fabricated for tPA in our laboratories and successfully could determine tPA in myocardial infraction and breast cancer patients. Graphical abstract Fabricated biosensor for determination of tPA.

Recent advances in nanomedicine and survivin targeting in brain cancers

Brain cancer is a highly lethal disease, especially devastating toward both the elderly and children. This cancer has no therapeutics available to combat it, predominately due to the blood-brain barrier (BBB) preventing treatments from maintaining therapeutic levels within the brain. Recently, nanoparticle technology has entered the forefront of cancer therapy due to its ability to deliver therapeutic effects while potentially passing physiological barriers. Key nanoparticles for brain cancer treatment include glutathione targeted PEGylated liposomes, gold nanoparticles, superparamagnetic iron oxide nanoparticles and nanoparticle-albumin bound drugs, with these being discussed throughout this review. Recently, the survivin protein has gained attention as it is over-expressed in a majority of tumors. This review will briefly discuss the properties of survivin, while focusing on how both nanoparticles and survivin-targeting treatments hold potential as brain cancer therapies. This review may provide useful insight into new brain cancer treatment options, particularly survivin inhibition and nanomedicine.

Clinicopathological significance of survivin expression in patients with cervical cancer: A systematic meta-analysis

BACKGROUND

Survivin has been shown to play an important role in cancer pathogenesis. However, its role in cervical cancer development is still controversial. This study was performed to evaluate the clinical significance of survivin expression in cervical cancer.

METHODS

Search of some online electronic databases was conducted to identify available studies. The pooled odds ratios (ORs) with its 95% confidence intervals (CIs) were calculated and analyzed.

RESULTS

Finally, 18 eligible studies with 791 cervical cancer patients, 1,013 cervical intraepithelial neoplasia (CIN) lesions, 199 normal cervical tissues, and 95 samples with chronic cervicitis were identified in this analysis. The pooled OR of survivin expression was found to be significantly higher in the samples from cervical cancer than in those from CIN lesions, normal cervical tissues, and chronic cervicitis. When cervical cancer was compared to CIN lesions, the subgroup analysis by ethnicity showed that survivin expression was associated with a risk of cervical cancer in Asians (P < 0.001), but not in Caucasians (P = 0.659). In addition, survivin was significantly more overexpressed in high-grade cervical cancer than in low-grade cervical cancer. Its expression was also more elevated in advanced-stage patients than in early-stage patients, in lymph node metastasis than in lymph node without metastasis, and in squamous cell carcinoma (SCC) than in adenocarcinoma (AC).

CONCLUSIONS

The expression of survivin may play a key role in the carcinogenesis, progression, and metastasis of cervical cancer. However, survivin expression may be involved in the progression of CIN lesions only in the Asian population. Survivin expression is associated with an increased risk of SCC. Additional studies with larger sample sizes are needed in the future to confirm our findings.

Exosome Proteome of U-87MG Glioblastoma Cells

Exosomes are small membrane vesicles between 30 and 100 nm in diameter secreted by many cell types, and are associated with a wide range of physiological and/or pathological processes. Exosomes containing proteins, lipids, mRNA, and microRNA contribute to cell-to-cell communication and cell-to-environment regulation, however, their biological functions are not yet fully understood. In this report, exosomes in the glioblastoma cell line, U-87MG, were isolated and the proteome was investigated. In addition, exosome proteome changes in U-87MG cells exposed to a low temperature were investigated to elucidate whether the exosome proteome could respond to an external stimulus. Cell culture medium was collected, and exosomes were isolated by continuous centrifugation eliminating cell debris, nucleic acids, and other particles. The morphology of exosomes was observed by cryo-tunneling electron microscopy. According to 2-dimensional electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry, certain proteins including collagen type VI alpha 1, putative RNA-binding protein 15B chain A, substrate induced remodeling of the active site regulates HTRA1, coatomer protein complex-subunit beta 2, myosin-heavy chain 1, and keratin-type I cytoskeletal 9 showed differences between the control proteome and the low temperature-exposed proteome.

Comparison of two fabricated aptasensors based on modified carbon paste/oleic acid and magnetic bar carbon paste/Fe3O4@oleic acid nanoparticle electrodes for tetracycline detection

In this research, we have improved two aptasensors based on a modified carbon paste electrode (CPE) with oleic acid (OA), and a magnetic bar carbon paste electrode (MBCPE) with Fe3O4 magnetic nanoparticles and oleic acid (OA). After the immobilization process of anti-TET at the electrode surfaces, the aptasensors were named CPE/OA/anti-TET and MBCPE/Fe3O4NPs/OA/anti-TET respectively. In this paper, the detection of tetracycline is compared using CPE/OA/anti-TET and MBCPE/Fe3O4NPs/OA/anti-TET aptasensors. These modified electrodes were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), UV-vis spectroscopy, and voltammetric methods. The linear range and the detection limit for TET with the CPE/OA/anti-TET aptasensor were found to be 1.0×10(-12)-1.0×10(-7)M and 3.0×10(-13)M respectively by EIS method. The linear range and the detection limit for TET with the CPE/OA/anti-TET aptasensor were found to be 1.0×10(-10)-1.0×10(-7)M with a limit of detection of 2.9×10(-11)M using differential pulse voltammetry (DPV) technique. The MBCPE/Fe3O4NPs/OA/anti-TET aptasensor was used for determination of TET, and a liner range of 1.0×10(-14)-1.0×10(-6)M with a detection limit of 3.8×10(-15)M was obtained by EIS method. Also, the linear range and detection limit of 1.0×10(-12)-1.0×10(-6)M and 3.1×10(-13)M respectively, were obtained for MBCPE/Fe3O4NPs/OA/anti-TET aptasensor using DPV. The proposed aptasensors were applied for determination of tetracycline in some real samples such as drug, milk, honey and blood serum samples.